Clinical Sonography III Practice Exam

Arterial inflow is about the blood supply entering the graft through the feeding artery. In a preoperative duplex study, the key sign of adequate inflow is a patent feeding artery with suitable diameter and robust, pulsatile flow on Doppler (velocity and, when possible, estimated flow). This indicates the graft will receive enough blood to mature and function. If inflow is limited by stenosis or occlusion, the graft is at high risk for thrombosis and failure. The other factors—venous outflow, vein size, and palmar patency—relate to drainage, the size of the outflow vein, and hand perfusion, respectively, but they do not quantify the arterial supply to the graft. Thus, the arterial inflow parameter directly reflects the incoming blood supply.